We did this for a previous 4e game I was running. Essentially I had a friend in Poland who wanted to play along side us, so we hooked up a laptop to the HDTV in the living room, and ran Skype for his webcam and my webcam (a Microsoft Lifecam Cinema), and plugged into a AT2020 USB microphone (this microphone picks up living room audio *beautifully*), so he can hear and see the living room.
However Skype is particular nasty about dumbing down the video quality when there are hiccups in the internet, so we couldn't use it for the gamebaord cam. I ended up buying a second Lifecam and tried tinychat (horrible quality) and then streaming with Justin.TV and Flash Media Encoder (nasty nasty delays). I ended up using a software called WebcamXP, which allows you to set up your machine as a streaming server and output the video stream to a browser (Chrome is recommended on the receiving end). Finally this allowed for little delay, high resolution (720p here :), and more than one user. Granted you still need a decent internet connection, but this worked out pretty well.
As far as mechanics worked, he rolled his dice on his end and managed his own character sheet. The only thing we did was move his mini where he wanted to go. He did have a webcam on his side, so we could actually see the rolls, and if he didn't think we'd believe him, he'd just pull the webcam off the monitor and point it at the dice.
In the future, I probably wouldn't use a camera for the gameboard. I'd keep the camera for the living room, but I'd keep a laptop with d20pro running, and just use minis and maps for the physical gameboard, and run a separate instance of the VTT for the online players to run, and just map the physical minis to their logical places on the grid in the VTT. Whenever a player or monster would move on the physical map, I'd move said token on the VTT, and when a remote player moved his token, I'd just move his respective mini. All the HP, initiative, and DM mechanics I'd simply run through the VTT. That way there's no shuffling around the camera and what not.
BTW, if you want to see how this equipment works in action, I'm using the same camera and microphone to record sessions of our recently formed Pathfinder Society chapter here in Houston. The nice part is since it's a condenser mic, it muffles background noises of whatever is behind it. Which in the case of these recordings, is great for tuning out the ambient noises of the rest of the store's crowd.
Hope this helps.
